1. Field of the Invention
This invention relates to an apparatus for transporting webs of random length and width along the path of a transport strip that is wrapped helically around one or more porous conduits.
2. Description of the Prior Art
U.S. application Ser. No. 490,155, now U.S. Pat. No. 3,968,510, by one of the present inventors, discloses a porous conduit web processing apparatus employing an enclosed conduit, such as a tube closed off at one end and having closely spaced openings, through which a liquid processing solution introduced into the center of the tube under pressure can reach the outer surface of the tube. Means are provided for directing a web helically around the periphery of the tube. When the liquid processing solution is directed outwardly through the openings in the tube, a liquid layer is formed between the outer surface of the tube and the web. Thus, the web that is helically wrapped around the tube is the web or film to be processed by the liquid processing solution emanating from the tube.
The above application also discloses guiding means for guiding and assuring transport of the web along the predescribed helical path. The disclosed guiding means accepts webs of random length but having a predetermined width. While the guiding means disclosed in said application perform their purpose adequately, they cannot accommodate random web widths.
Dutch Pat. No. 66,953 discloses a processing apparatus in which the web to be processed is guided through various processing solutions by an advancing metal band to which the film adheres. The metal band is not supported as it passes through the processing solutions; the rigidity of the metal band is relied upon to maintain the proper path. Nevertheless, the metal band is flexible and subject to drafts and vibrations causing the band to oscillate, thereby resulting in inconsistent agitation and uneven development. In addition, the processing apparatus is not suitable for random lengths of film since a certain amount of film tension is required to keep the film adjoined to the metal band. In fact, only relatively long lengths of film may be conveniently processed in this disclosed processing apparatus.